1. Field of the Invention
The present invention relates to a method of yarn processing position control of a flat knitting machine for processing the yarn by a knotter or the like to change over by coupling an exchange or new yarn with a yarn previously fed for knitting, to enable knitting of an intarsia pattern or the like by using the processed yarn, and to apparatus for executing such method.
2. Description of the Related Art
Hitherto, when knitting an intarsia pattern or a stripe pattern, colors are changed by coupling a new yarn to an existing yarn, during the knitting process, by a knotter provided in the knitting machine. Such prior art arrangement is disclosed, for example, in Japanese Examined Patent Publication JP-B2-1990-14455 (PCT/EP82/00083) or Japanese Unexamined Patent Publication JP-A-1988-270846 (DE-P3712264.9).
According to the prior art arrangement disclosed in Japanese 1990-14455, a stripe-like pattern with changed colors is knitted by a circular knitting machine. Knitting is done by a cylindrical rotary needle, and a drum is provided between a knotter and a cylinder in order to retain yarn at an intermediate position. The peripheral length of the cylinder is constant, and the required length of the yarn is determined by the product of this length and the number of stages for knitting the strip-like pattern. The knotter changes over the yarn when feeding the yarn by this length. While the knotter is working to change over yarn, the yarn preliminarily retained in the drum is fed to the cylinder, so that the knitting operation does not stop.
According to the prior art arrangement disclosed in 1988-270846, by splicing the yarn while knitting by a flat knitting machine, patterns of changed colors are knitted. Where yarn splicing is desired, the knitting machine is stopped, and the yarn is spliced at a position upstream of a knitting needle. Yarn from the position of the yarn being fed to the knitting needle to a position exceeding the coupling point is drawn into a yarn drawing device provided at one end of the needle bed. The drawn yarn is confined, and the knitting machine is started again to resume knitting, and the drawn portion of the yarn then is cut off.
According to the above-mentioned prior art arrangements, within one knitting course of fabric, a stripe-like pattern without yarn changeover can be favorably knitted. However, various problems occur when knitting an intarsia pattern fabric 1 as shown in FIG. 10. In the intarsia pattern fabric 1, plural colors are used in one knitting course in the horizontal direction in FIG. 10. In the lower knitting course, there exist white yarn fabric 2, red yarn fabric 3, and yellow yarn fabric 4. In the upper knitting course, there exist white yarn fabric 2, blue yarn fabric 5, and yellow yarn fabric 4. In the prior art arrangement disclosed in Japanese 1990-14455, although knitting of a stripe-like pattern is possible, intarsia pattern fabric 1 cannot be knitted. In the prior art arrangement disclosed in Japanese 1988-270846, the knitting operation must be stopped when changing over the yarns of various colors, and the yarn must be drawn out and spliced.
When knitting the intarsia pattern fabric 1 shown in FIG. 10, if using different yarn feeders for each color, problems when changing over the yarns do not occur. In such case, to knit the intarsia pattern fabric 1, yarn feeders for four colors must be prepared. However, since the red yarn and blue yarn are not knitted simultaneously, by coupling the red yarn and blue yarn in one yarn feeder, it is possible to knit by using three yarn feeders in total. This concept can be employed when using more color yarns. In order that coupling is at the changeover position of the red yarn fabric 3 and blue yarn fabric 5, the knitting operation of the knitting machine may be stopped at that position, and the yarns may be changed over as in the prior art arrangement disclosed in Japanese 1988-270846. However, when drawing out and processing the yarn, the knitting operation must be stopped, and the cut portion of the yarn is wasted. Moreover, since a yarn drawing device is needed, the construction of the apparatus and the control for the apparatus are complicated.